Heater construction for kiln or other apparatus



, 19 1 J. J. GREGORY April 25 HEATER CONSTRUCTION FOR KILN OR OTHERAPPARATUS Filed OCT,- 25, 1957 5 Sheets-Sheet 1 4 INVENTOR.

JAMES J. GREGORY BY Qa, W 4, Z A M A ril 25, 1961 J. J. GREGORY2,981,819

HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS Filed Oct. 23, 1957 5Sheets-Sheet 2 INVENTOR. i n a JAMES :J. GE'GOflf ATTORNEYS April 25,1961 J. J. GREGORY 2,981,819

HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS Filed Oct. 25, 1957 5Sheets-Sheet 4 INVENTOR. JAMES J. GREGORY A Tl'OE/VEYS United StatesPatent HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS James J. Gregory,21570 Edgeclitf Blvd, Euclid 23, Ohio Filed Oct. 23, 1957, Ser. No.691,991 16 Claims. (Cl. 219-35) This invention relates to a heaterconstruction and more particularly to a portable kiln usable for heatingenamels, ceramics, metals, and other objects or articles.

An object of the present invention is to provide a kiln or other typeheating construction especially adapted for heating ceramic, enamel,clay, porcelain, frits and glazes; adapted to be used in the ceramicfield, of light weight; having a short heat-up period; requiring nogloves for loading or unloading, having a low heat reservoir; havingcomponents protected against burn-out; having no harmful ultra-violetrays; inexpensive to operate; safe to operate under all workingconditions; adapted to be used for its intended purpose with aconstruction having a minimum of insulation and a minimum of basicframework; and adapted to be used for enameling, glazing,porcelainizing, or brazing localized areas on large objects.

A further object of the present invention is to provide a heaterconstruction or kiln characterized by its structural simplicity, economyof manufacture, ease of assembly of its component parts, strong andsturdy nature, and operating eificiency.

Other features of this invention reside in the arrangement and design ofthe parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from theaccompanying drawings and description and the essential features will beset forth in the appended claims.

In the drawings,

Fig. 1 is a front elevational view of a kiln portraying the presentinvention;

Fig. 2 is a side elevational View, partially in section, looking towardthe right at the left-hand side of the kiln in Fig. 1;

Fig. 3 is a vertical sectional view taken along the line 3-3 of Fig. 2through the kiln;

Fig. 4 is a vertical sectional view taken along the line 44 of Fig. 1;

Fig. 5 is a top plan view, partially in section and taken generallyalong the line 55 of Fig. 4, of the kiln with the coolinghood removed;

Fig. 6 is an electrical diagram of the radiant heating lamps and airblower fan; while Fig. 7 is an enlarged sectional view of a portion ofthe reflector in Fig. 3."

Before the construction here illustrated is specifically described, itis to be understood that the invention here involved is not limited tothe structural details or arrangement'of parts here shown sinceconstructions embodying the present invention may take various forms. Italso is to be understood that the phraseology or terminology hereinemployed is for purposes of description and not of limitation since thescope of the present invention is denotedv by the appended claims.

While the present invention might be adapted to various types of uses, Ihave chosen to show the same as ap-.

plied to a kiln for heating objects and/ or fusingceramic,

'ice

enamel, clay, porcelain, frits and glazes. It should also be apparentthat all or portions of the heater construc tion disclosed hereinaftermay be used for cooking foods, for fast thawing frozen ore cars prior todumping, for heating conveyed materials, for heating containers ofmaterials, etc.

The kiln or furnace herein may be constructed of any conventionalmaterials but is disclosed specifically herein as constructed ofsuitable refractory materials supported by a metal superstructuredescribed hereinafter as a base housing 10.

Base housing 10 has four parallel corner members 11, 12, 13 and 14, eachL-shaped in cross section, located at respective corners of a rectangle,as shown in Fig. 5. These corner members have respective correspondingflanges 11a, 11b, 12a, 12b 13a, 13b, 14a and 14b. Adjacent flanges aremutually coplanar, for example, flanges 11a and 12b are coplanar in Fig.5, to form a channel 16 rectangular in cross section, as shown in Fig.5. This channel 16, rectangular in cross section, has an upper open end16a and an at least partially closed lower end 16b, as shown in Figs. 3and 4.

Base housing 10 has four connecting members 21, 22, 23, and 24, eachL-shaped in cross section, secured at opposite ends respectively toadjacent corner members.

For example, connecting member 21 is shown being secured at oppositeends to flanges 11a and 12b of corner members 11 and 12. This securementcan be by any suitable type connecting means but is shown herein as awelded connection between the component members. Each connecting memberis L-shaped in section with a bottom flange designated by the referencenumeral a and with the side flange designated by the reference numeralb, such as connecting member 24 in Fig. 3 having bottom flange 24a andside flange 24b. Side flanges 21b, 22b, 23b and 24b form the sides ofthe rectangular channel 16; bottom flanges 21a 22a, 23a, and 24a arecoplanar and form the border closed bottom end 1611 of the channel 16.Here the upper ends of the corner members 11, 12, 13 and 14, remote fromclosed end 16b, form the open end 16a of the channel. Each corner member11, 12, 13 and 14 has a portion thereof extending down below the plane,formed by flanges 21a24a, to form supporting legs 11 12 13 and 141 forthe kiln.

Base housing 14) has a front side 18a in Fig. l, bordered by members 11,12 and 21, forming one side of the rectangular channel 16 and formingthe front side of the kiln.

On front side 10a, lower and upper channel members 27 and 28, eachU-shape in cross section in Figs. 2 and 4, are connected in parallelrelationship with their channel openings facing each other by beingwelded or otherwise secured at opposite ends to the corner members 11and 12 forming the opposite edges of the front side 10a. Two doors 29,29 are slidably connected in the U-shaped channels of members 27 and 23and are adapted to be moved by handles 30 secured thereto between thekiln closed position in Fig. 1 with these doors 29 in abuttingrelationship and a kiln open position with the doors in spaced apartrelationship to permit loading of the kiln with objects to be heated.

This base housing 10 may also include extra plates for support such asbottom plate 32 in Figs. 3 and 4 closing channel end 16b resting uponthe coplanar flanges 21a24a and a back plate 34 resingagainst thegenerally coplanar flanges 13a, 14b and 23b.

An assembled unit 36 is adapted to be mounted within the base housing10. This assembled unit 36 has interconnected walls including a backwall 38, a bottom wall 39, a top wall 40, a front wall 41 and oppositeside walls 45 and 4 6 forming heating zone or enclosed heating chamber47 therebetween. Front'wall 41 includes top connecting means or top beam42 and doors 29. Top connecting means 42 forms with bottom wall 39 andopposite walls 45 and 46 an open front for chamber 47 for kiln loadingwith this open front adapted to be closed by doors 29. The opposite sidewalls 45 and 46 include respectively base portions 45a and 46a havingrecesses formed in their top and outer surfaces, connecting bars 45b and461) secured at opposite ends to the bases 45a and 46a, and channels 450and 46c between the respective connecting bars and bases. A suitableheat source 49 is located within the heating chamber 47 to provide theheat desired therein. Bottom wall 39, back wall 38, front wall top beam42, opposite side wall bases 45a and 46a, and opposite side wall bars45b and 4612 are shown herein as formed of refractory material, such asfire bricks, but may be formed of any other suitable heat resistantmaterial of low heat conductivity, such as any suitable ceramics. Theselast-mentioned walls, bases, bars and connecting beam are suitablycemented together in the assembled form to form assembled unit 36 andthe enclosing heating chamber 47.

Top wall 40, extending across the rectangular channel 16 and locatedclosest the channel open end 16a, is a suitably curved reflector. Thisreflector may be of any suitable type and shape and is adapted to coactwith a heat source 49 comprising one or more infra-red lamps 50. Thereflector 40' may include a single downwardly concave curve with asingle heat lamp 59 located within the curve or a plurality of lamps 59,shown as four in number in Fig. 4. The reflector 40 may have a pluralityof downwardly facing concave curves laterally spaced apart, eitherseparate or interconnected, instead of the single concave curve shown inFig. 4. Each concave curve of this multiple curve reflector may have asingle or a plurality of heat lamps 54 within the curve. The concavecurve of the single type or each concave curve of the multiple type maybe parabolic, eliptical, hyperbolic, dish-shaped or any combinationthereof. However, the choice of reflector curve; the number of concavecurves in the reflector; and the relative location between the focus ofthe curves, the lamps and the top of bottom wall 39 must be chosen togive the desired heat concentration on the object to be placed on wall39 and in the preferred location on wall 39.

The reflector 49 may be formed of any suitable material, but ispreferably formed of heat conductive material for reasons to be moreapparent hereinafter. it may be formed of metallic or non-metalliccomposition provided it has proper emissivity or reflectivecharacteristics. The reflector of proper curvature can be formed overpatterns cast or machined. Its reflecting surface may be coated with ahigh reflective, low oxidation potential ma terial, such as gold,platinum, etc., using the vapor deposition, electrolytic or any othermethod suitable for the application of the coating. One suitablereflector, and the form preferred in the present construction, is ametallic Alzak reflector of the conventional type wherein a sheet ofaluminum has its reflecting sides 4hr in Figs. 3, 4 and 7 processed asfollows. First, an electrolytic brightening treatment is applied touniformly remove a very thin layer of metal from the surface and anyforeign material which may have become imbedded in the surface duringfabrication of the reflector. maximum reflection. Second, this cleanaluminum surface is then protected by an electrolyticanodic oxidecoating to provide a glass-like, transparent, weather resistant andcleanable surface showing the bright, underlying metal as a reflector.The resulting construction is shown in Fig. 7 wherein the reflector 40has an aluminum base 49a with an oxide coating 40b on the reflectingside 40r thereof so that the reflector has high reflectivity with thisoxide coating 4012 having a higher meltingpoint than the aluminum basefla.

The radiant energy, infra-red, heat source 49 may be of any suitabletype for creating the desired high opera ing temperature in the enclosedheating chamber 47 but is preferably one or more electric, infra-red,radiant energy lamps 54), four being shown in the present disclosure.Each is mounted in the opposite side walls 45 and 46 in the heatingchamber 57 in spaced relationsihp to the reflector 40 on the reflectingside 40; thereof for emitting radiant energy against tthis reflectingside 40r over the reflecting surface area bounded by back wall 38, fronttop beam 42, and opposite side walls 45 and 46 so as to obtain a heatconcentration on a plane or irregular surface slightly above the bottomwall 39 upon which the object to be heated will rest for fusingporcelain, enamels, and glazes thereto or fusing fire clays or ceramics.Lamps 50 may be of any suitable type, but each is preferably of the typedisclosed in the United States Patent entitled Electric Radiant EnergyDevice patented by A. G. Foote on February 15, 1954 as Patent No.2,342,044. This type lamp has a quartz, or other suitable vitreousmaterial, envelope 5nd having opposite ends, being tubular in form andhaving a longitudinal central axis Sflf. This lamp has a suitable means5nd, as disclosed in said patent, for transforming electrical energyinto radiant energy, which means extends through envelope Sfla alongaxis 50f and is operatively connected to the two electrically conductiveterminals 501) and 500 operatively secured to the opposite ends ofenvelope Sfla along the source axis 50f. Each lamp 5%) may have either aclear or opaque vitreous envelope 56m and may be usable on any suitablevoltage or phase circuit. If desired, a rheostat, either manually orthermostatically controlled or a combination thereof, can be applied inthe energizing circuit of these lamps 50 in Fig. 6 so that the deisredtemperature will be maintained in the enclosed heating chambers 47.

The terminals 50]; and 59c are supplied by electric power throughsuitable leads 51 and 52 in Figs. 3, 5 and 6 from a common electricalpower source. The leads to these respective terminals Stib and 590include respectively bus bars 51:: and 52a, secured in appropriategrooves formed in the top of the opposite side walls 45 and 46 andconnected to the electric source by power lines and 56, and includebranch wires 51b and 521) secured at one end by connecting screws 51cand 52c to the bus bars 51a and 52a and at the other end by connections53 and 54 to the associated lamp terminals 56b and 500.

The aforesaid patented infra-red, radiant energy heat lamps 59 areespecially well adapted for the purpose described and illustratedbecause they come up to full temerature ahnost instantly, when energizedto a heat emitting relationship, for creating the high operatingtemperature desired Within the heating chamber 47 but still lose about80% of their radiant energy within a few seconds after turn-off. Also,the quartz envelopes 50a resist high temperatures so that the enclosedheating chamber 47 may become very hot without damaginglamps 56. Forexample, quartz softens at 3000 degrees Fahreinheit in contrast with theordinary light bulb glass softening at 840 degrees Fahreniheit.

Suitable structure is provided for mounting reflector 4t) and lamps Sitin the opposite side walls 45 and 46 for con- This develops venientassembly and to provide a multiplicity of advantages. These oppositeside walls 45 and 46- have extending through their faces coaxiallyaligned bores 45m and 46m respectively for mounting each lamp 50 inspaced relationship to the reflecting side 40r of reflector 4t) andwithin the enclosed heating chamber 47 but with each lamp 5t protrudingthrough the opposite side walls 45 and 46 in the manner shown in Figs. 3and Sso that both terminals 50b and 500 thereof, leads 51 and 52, andconnections 53 and54 are located outside the opposite side walls 45 and4-6 from the heating chamber 47. Suitable sleeves 57 and 58 surroundeach lamp tubular envelope 50a in the aligned bores 45m and 46m formounting the lamp 50 therein and preventing escape of the heat fromwithin the heating chamber47f These sleeves may be formed of suitableasbestos, fire brick, or ceramic type cement material forced within thebores around the tubular lamps to mount the longitudinal central axis 50of each lamp 50 coaxial with the aligned bores 45m and 46m.

Reflector 40 has its opposite ends mounted in straight groves 38n inback wall 38 and groove 42m in the front top connecting beam 42, and hasits sides mounted in the arcuate grooves 45n and 4611 of the side walls45 and 46. It should be noted that the reflector 40 is shaped in a curvewith the elements of the curve, shown as straight horizontal lines inFig. 3, extending parallel to an axis or axes coinciding with orextending parallel to the longitudinal axes 50 of the lamps 50 so as tobe symmetrical therewith. These aligned grooves 45:1 and 4611, formed onthe inner surfaces of the side walls 45 and 46, also have their elementscoinciding with the elements of reflector 40 and extending parallel tothe axes of the aforesaid aligned bores 45m and 46m and to thelongitudinal axes 519]. The grooves are curved in a plane transverse tothe axis of the bores and along the same curve as the reflector 49.Hence, assembly of the unit 36 is easily achieved by moving the oppositeside walls 45 and 46 toward each other by approach movement along theaxes of bores 45m and 46m, while reflector 40 and lamps 50 are properlylocated in their respective groves and bores, and are disassembledbyseparation movement of these side walls. This is possible because theaxes of the bores, lamps, reflector curve, and mounting grooves areoriented in the same direction.

In addition to providing convenience of assembly and disassembly, thismounting construction permits the reflector 40 to operate at a highertemperature and to be properly shielded for proper cooling as willbebrought out in more detail hereinafter. The reflector. will operate ata higher temperattue because the oxide coating 40b in Fig. 7, having ahigher melting point than the aluminum base 49a, has not been pierced bymounting fasteners for the reflector; because no joined dissimilarmetals exist to melt at their junction at a lower temperature thaneither alone by the so-called eutectic eifect because the reflector 40has only one metal, aluminum; and because the aluminum oxide coating,having a higher melting point than aluminum, is not pierced by and isfree of any material having a greater heat conductivity. Also, the sidewalls 45 and 46, back wall 38 and front wall portion 42 serve as ashield for the reflector 40 to expose only the desired reflectingsurface area 401' to the lamps 50 while the remainder thereof isshielded by ceramic or fire brick material having high heat resistanceand low heat conductivity characteristics.

The assembly of the unit 36 into the base housing should be readilyapparent. After the side walls 45 and 46 have been moved toward eachother to properly mount reflector 40 and lamps 50, then fire brick walls38, 39, 40, 42, 45 and 46 will be cemented or otherwise secured togetherto form the assembled unit 36. Then, after plates 32 and 34 are placedin channel 16 in their final positions, the assembled unit 36 may betelescoped into the rectangular channel 16 through its open end 16auntil its bottom wall 39 engages bottom plate 32 supported by bottomflanges Zia-24a.

Alternate constructions readily suggest themselves. Lamps 50 andreflector 40 may be placed in any suitable position around the enclosedheating chamber 47 with the reflector 4t and lamps 50 being substitutedas a wall for the bottom wall 39, back wall 38, or either side wall 45or 46 depending on the need, size and shape of the object being heatedwithin chamber 47. For example, in bottom heating wherein reflector 40serves as a bottom wall, it is preferred that a clear quartz, vycor orany high melting borsilicate glass plate of inch to /2 inch thickness beused to act as a shield for the heat source and to support the objectbeing heated. This glass plate is preferably of the proper opticalproperties (ground and polished), which may as the occasion arisesdifluse' or concentrate the light heat energy over the plane or surfaceformed by the object being heated. Also, lamps and reflectors may beused simultaneously in a plurality of the walls forming the heatingchamber 47, such as opposite side and top walls. Also, for kilns orfurnaces of the simplest design, lamps 50 and reflector 40 may besupported by a skeleton construction on vertical supports, such as inany suitable manner by corner members 1114, without any substantiallyenclosing fire brick or insulating construction such as back wall 38,bottom wall 39, etc. This type construction will facilitate making akiln or furnace for any size or geometric shape desired for immediateuse with minimum of economic expenditure. However, it should be realizedthat when the lamps 50 are deenergized, the object previously heated inthis skeleton construction will cool rapidly since it is not enclosed ina heating chamber 47 and hence crazing may occur.

In operation of the kiln or furnace at the high temperatures desired, itis necessary to cool some of the component parts in a suitable mannerand especially to cool the reflector 40, terminals 50b and 500, leads 51and 52, and connections 53 and 54 to protect them against overheating.Herc, means is provided for cooling the reflector and these othercomponent parts by the circulation of coolant fluid in the manner shownby the arrows in Fig. 3. Although this coolant fluid may be any type gasor liquid, it is shown herein as air. This means includes a hood 60operatively connected by telescopic association of its flanges 66a and66b over the rectangular cross sectioned periphery, formed by walls 38,42, 45 and 46 of unit 36, into abutting relationship with the top ofcorner members 1114 of base housing 10 for closing the upper openchannel end 16a of base housing 10 and includes an electrically drivencoolant pump or blower 62, comprising an electric drive motor 62a and ahousing 621) for an impeller driven by said motor, mounted on hood 60for sucking in air and for driving it into the hood 60 to ,circulatealong a path through the hood, over and in thermal contact with asurface on the upper or other side of the heat conductive reflector 40from heat lamps 56 approximately coextensive with and approximatelyaligned with reflecting surface 401-, as bounded by walls 38, 42, 45 and46, so that the cooled surface is approximately coextensive with thesurface receiving the radiant energy; over at least a portion of theleads 51 and 52; over connections 53 and 54; over terminals 5% and 50c;through channels 450 and 460 in the side walls 45 and 46 formed betweenside wall bases 45a and 46a and side wall bars 451) and 46b; over atleast a portion of the outer surface of the opposite side Walls 45 and46; and through opposite apertures in the base housing ll) formedbetween adjacent corner members 11, 14 and 12, 13 for reducing theoperating temperature of the reactor, connections, leads and terminalswhile the side walls 45 and 46 shield the vitreous envelopes 59a oflamps 50 from coolant contact and while reflector 40 and side walls 45and 46 prevent entry of the coolant into the enclosed heating chamber47. Hood lips 600, depending from and integral with hood flanges 6%,close the upper ends of the discharge passageways of channels 450 and460 so as to direct the cooling air against terminals 5% and 50c andagainst leads 51 and 5'2 located in the corners of channels 450 and 460to assure adequate cooling thereof. This cooling action permits the kilnto operate at a high temperature while protecting the components thereoffrom overheating. For example, reflectors 40 may be heated to 1600degrees Fahrenheit, well over the melting point of aluminum, with theaforementioned type lamps 50 if blower or pump 62 is not energized.However, when the blower 62 is circulating the coolant fluid along theflow path shown by the arrows in Fig. 3, the temperature of thereflector 45 may drop to 300 degrees Fahrenheit.

Alternate methods of cooling the reflector readily suggest themselves,In Fig. 3, pump or blower 62 forces the air as a coolant fluid along thepath shown by the arrows to cool the components and to displace the hotair within the hood. Instead, pump 62 may be used as an exhaust pump tosuck the cool air in through the openings in the side walls 45 and 46 sothat the flow will be along the same path but in the opposite directionto the arrows. Also, the circulated coolant fluid might take the form ofwater or other suitable refrigerant circulating through pipes in thermalcontact with the upper surface of reflector 40 and in the generalenvironment of the terminals 56b, 56c and leads 51 and 52. Also, coolingby circulation of coolant fluid may be obtained by placing thin sectionsof a metallic or non-metallic, high thermalconductivity material on thereflector and the other components desired to be cooled so that heat maybe drawn away from the component to the surface thereof most remote fromheating chamber 47 by the normal course of thermal transmission in thematerial. This cooling may be accelerated by the use of a mechanicallydriven fan or blower, either sucking or blowing cool air over the thinsections.

The electric circuit controlling lamps 50 and blower, fan or pump 62 isshown in Fig. 6. Power to both is supplied through power lines L1 and L2through a double pole double throw switch 64 having three positions: (1)lamps t and blower 6t deenergized, (2) blower 62 energized and lamps 5tdeenergized, and (3) lamps 5! and blower 62 energized. The switch 64 isshown in Fig. 6 in its first position. The second position is achievedby swinging the switch 64 counterclockwise into engagement with itsleft-hand contacts to complete its circuit from power line L2 throughthe lower switch arm, line 65, blower 62, and line 66 to power line L1.The third circuit is completed by swinging the switch clockwise in Fig.6 into engagement with its right-hand contacts to complete a circuitfrom power line L2 through switch jumper 64a, the upper switch blade ofswitch 64 and through two parallel paths back to power line L1 with oneof the parallel paths extending through switch jumper 64b, the lowerblade of switch 64, line 65, blower 62 and line 66 to energize blower 62and with the second parallel path extending through line 55, bus bar51a, branch wires 51b, connections 53, lamps 50 connected in parallel,connections 54, branch wires 52b, bus bar 52a, and line 56 to energizelamps 56. Hence, it should be readily apparent that the reflector andother components of the kiln are protected against overheating at alltimes since this circuit prevents energizing the radiant energy lamps 50without energizing the coolant fluid pump or blower 62 so that the fanor blower will always operate While the enclosed chamber 47 is beingheated by the energized lamps 50. It should be readily apparent that athermalcouple wire junction may be used to check the temperatures ofreflector 4t), terminals 50b and 560, leads 51 and 52, and the enclosedheating chamber 47 to open or close one or both of the parallel circuitsin Fig. 6 from switch 64 through lamps 5i) and blower 62 to protect thecomponent parts of the kiln from overheating and to control thetemperature within the enclosed heating chamber 47.

The use of the kiln should be readily apparent. Switch 64 is thrown tothe right-hand position in Fig. 6 to energize both the blower 62 andlamps 59. Since the lamps 50 heat up instantaneously, the object to beheated may be placed directly under the infra-red lamps 56 by placing iton top of the bottom wall 39 within the heating chamber 47 when doors 29are in their open position. The surface of the object and the top ofbottom wall 39 are so located as to obtain a heat concentration on 'aplane or on the irregular surface of an object at a distance from thereflector 4% and lamps 50 determined by the distance from the focus ofthe reflector curve. enamels will fuse upon the heated object within oneto four minutes. If many colors are to be used,'it is best to applylight colors first, fire the object, and then apply Most the dark colorslater, such as in cloisine work. This is true because the various colorshave different absorption properties. However, in most cases, all colorscan be applied together. ron, silver, copper, gold and other metals canbe used for enameling with this kiln.

The illustrated kiln construction has many advantages. First, the timerequired to bring the kiln to temperature is a matter of seconds asopposed to hours required to bring the conventional kiln to theoperating temperature prior to the time one may insert materials forenameling, glazing, fritting, ceramic firing, porcelainizing, etc.

Second, the object to be heated may be loaded by the user without glovesinto the heating chamber 47 at operating temperature. Unlikeelectrically wired kilns or muflie furnaces, the interior is not hotbecause the heating action takes place only when infra-red energy comesin contact with the object. This minimizes danger of burns, fires, etc.

Third, sineea long heat-up period is not required, the wall temperaturesare kept to a minimum and minimum insulation is required. However, sincefire brick has een provided in the walls in the illustratedconstruction, the object may be cooled slowly in the enclosed heatingchamber 47, if desired, without any danger of crazing. However, itshould be readily apparent that the major portion of the fire brickwalls may be completely eliminated from the construction so that theheating chamber 47 becomes a heating zone bounded by the structuralmembers of base housing 10 if crazing is no problem and a moreinexpensive kiln is desired. However, the low ,heat reservoir of theillustrated kiln, with its short heatup time, permits completion of theenameling or finishing of the ceramic within a very short time after thelamps 50 are energized. The object can be economically heated quickly inthe heating chamber 47 to the desired high operating temperature andhave the coating baked thereon in a minimum time.

Fourth, reflector 4t) and the other components are protected againstdamage by overheating. The reflector 40 is shielded by walls 38, 42, 45and 46 to expose only the reflecting surface area thereof which islocated directly opposite the upper surface having the circulatedcoolant impinged thereon. Hence, cooling takes place where the heat isthe greatest and cooling takes place over the entire heated area. Also,reflector 40 is mounted in grooves in the ceramic or fire brick walls sothat there will be no tendency to burn out at the mounting zones.

Fifth, this heat source 49 provides no harmful ultraviolet rays emergingfrom the heating chamber 47. Hence, colored glasses are not necessarybut are helpful.

Sixth, the cost of construction is considerably cheaper than the cost ofconstruction of an electrical resistance type or gas fired typeconventional kiln.

Seventh, the cost of operationof this kiln would be a small fraction ofthat required for the operation of the conventional gas or electric typekiln because a low heat reservoir is required and the absolute minimumof energy to heat the object is used. Hours of initial heating areeliminated. I

Eighth, this kiln is safer to use than the conventional electricalresistance or gas fired kiln. There is no hazard of sagging electricalcoils, which can be shorted, and there is no hazard of a gas explosion.

Ninth, localized areas on large objects may be enameliZed, glazed orporcelainized with this kiln or other heater constructions following theillustrated construction principles but having an open bottom adapted tobe pressed against the localized area of the large object to be locatedat a proper distance from the focus Q of aluminum; making reflector 40and hood 60 of aluminum; and making walls 38, 39, 40, 42 45 and 46 offire brick.

Various changes in details and arrangement of parts can be made by oneskilled in the art without departing from either the spirit of thisinvention or the scope of the appended claims.

What I claim is:

1. In combination, a reflector, an electric radiant energy heat sourcelocated in spaced relationship to said reflector on one side of saidreflector for emitting radiant energy against said reflector for heatingan object to a high temperature in a heating zone, said radiant energyheat source comprising a vitreous envelope having opposite ends, havingtwo electrically conductive terminals operatively secured to saidopposite ends of said envelope, and having means for transformingelectrical energy into radiant energy extending through said envelopeand operatively connected to said terminals, leads from a commonelectrical source to each of said terminals, an electrical connectionbetween each lead and its assooiated terminal, means for circulatingcoolant fluid in thermal contact with the other side of said reflector,at least a portion of said leads, said connections, andsaid terminalsfor reducing their operating temperatures, and means for preventingcoolant fluid circulation through said heating zone to reduce thetemperature thereof.

2. In combination, opposite walls forming a heating zone therebetweenfor temperatures of at least 1000 C., a reflector formed of heatconductive material, an electric radiant energy heat source in saidheating zone locatedin spaced relationship to said reflector on one sideof said reflector for emitting radiant energy against a reflectingsurface area on said one side, said electric radiant energy heat sourcecomprising a quartz envelope having opposite ends, having twoelectrically conductive terminals operatively secured to said oppositeends of said envelope, and having a tungsten filament extending throughsaid envelope and operatively connected to said terminals fortransforming electrical energy into radiant energy and located in inertgas sealed in said envelope, leads from a common electrical source toeach of said terminals, an electrical connection between each lead andits associated terminal, means operatively connecting said source andsaid reflector to said walls so that said walls serve as a reflectorshield to expose only saidreflector surface area on said one side tosaid source, said opposite walls being formed of heat resistant ceramicmaterial of low heat conductivity, said source being sufficiently highin temperature to melt said re flector and leads and connections andterminals if they are not cooled, means for circulating coolant fluidalong a path over and in thermal contact with a surface on the otherside of the reflector from said source approximately coextensive withand approximately aligned with said surface area, over at least aportion of said leads, over said connections, and over said terminalsfor reducing their operating temperatures belowrtheir 'melting pointwithout cooling said envelope and heating zone, means for preventingcirculation of said coolant fluid in said heating zone, and means forpreventing energizing said radiant energy heat source without energizingsaid coolant fluid circulating means.

3. In a structure adapted to heat an object to a high temperature,interconnected opposite and connecting walls forming atleast a portionof a heating zone, at least one of said connecting walls comprising areflector formed of heat conductive material, an electric radiant energyheat source mounted in said opposite side walls in said heating zonelocated in spaced relationship to said reflector on one side of saidreflector for emitting radiant energy against a reflecting surface onsaid one side, said electric radiant energy heat source havingterminals, leads from a common electrical source to each of saidterminals, an electrical-connection between each lead and its associatedterminal, said source protruding through both of said opposite wallswith both said terminals and leads being located outside said oppositewalls and said heating zone, means for circulating coolant fluid along apath over a surface on the other side of the reflector, over at least aportion of said leads, over said connections, and over said terminalsfor reducing their operating temperatures, and means for preventingcoolant fluid circulation through said heating zone to reduce thetemperature thereof.

4. In a structure adapted to heat an object to a high temperature,interconnected opposite and connecting walls forming at least a portionof a heating zone, at least one of said connecting walls comprising areflector formed of heat conductive material, an electric radiant energyheat source in said heating zone located in spaced relationship to saidreflector on one side of said reflector for emitting radiant energyagainst a reflecting surface on said one side, said electric radiantenergy heat source having terminals, leads from a common electricalsource to each of said terminals, an electrical connection between eachlead and its associated terminal, said source protruding through both ofsaid opposite walls with both said terminals and leads being locatedoutside said opposite walls and said heating zone, means operativelyconnecting said source and said reflector to said walls so that saidwalls serve as a reflector shield to expose only said reflector surfacearea on said one side to said source, power driven forced circulationmeans energized independently of the heat from said source forcirculating coolant fluid along a path over a surface on the other sideof the reflector from said source approximately coextensive with andapproximately aligned with said surface area, over at least a portion ofsaid leads, over said connections, and over said terminals for reducingtheir operating temperatures, and means for preventing coolant fluidcirculation through said heating zone to reduce the temperature thereof.

5. In combination, opposite walls, a curved reflector with the elementsof the curve extending parallel to an axis, and an energy source foremitting energy against said reflector and being tubular in form with alongitudinal. axis, said opposite walls having through their inner facescoaxially aligned bores wherein said tubular energy source is mounted,said opposite side walls having in their inner surfaces aligned groovesextending along their elements parallel to the axis of said bores andcurved in a plane transverse to the axis of said bores along the samecurve as said reflector wherein opposite ends of said reflector aremounted, whereby said opposite walls, reflector and energy heat sourceare assembled by approach movement of said walls along said bore axiswith the axes of said bore, source and reflector curve oriented in thesame direction and are disassembled by separation r movement of saidopposite walls.

6. In a kiln, a base housing comprising four parallel corner memberseach L-shaped in section and located at respective corners of arectangle with adjacent flanges mutually coplanar to form a channelrectangular in cross section, and four connecting members secured atopposite ends respectively to adjacent corner members and each beingL-shaped in section to form with one flange of each L-shape sides of therectangle and with the other 7. In a kiln, a base housing having achannel with an i open end; a unit having interconnected walls formingat least a portion of a heating zone With said unit adapted to betelescoped into said channel open end into assembled relationship intosaid base housing, one of said walls extending across said channel andbeing located closest said open end being a reflector, and a radiantenergy heat source in said heating zone located in spaced relationshipto said reflector for emitting radiant energy against said reflector; ahood operatively connected by telescopic association to said unit andbase housing for closing said open end of said base housing; and acoolant fluid pump for circulating coolant fluid through said hood andalong a path over a surface on the other side of the reflector from saidsource for reducing the operating temperature of said reflector.

8. In a kiln, a base housing comprising four parallel corner memberseach L-shaped in section and located at respective corners of arectangle with adjacent flanges mutually coplanar 'to form a channelrectangular in cross section, and four connecting members secured atopposite ends respectively to adjacent corner members and each beingL-shaped in section to form with one flange of each L-shape sides of therectangle and having the other respective flanges coplanar to form aborder closed bottom end of the rectangular channel with an open upperend, said corner members extending down beyond said plane to formsupporting legs for said kiln; a unit having interconnected wallsforming at least a portion of a heating zone with said unit adapted tobe tclescoped into said channel openend into assembled relationship intosaid base housing and supported at the bottom by said second recitedflanges of said connecting members and laterally by said corner membersand first recited flanges of said connecting members, one of said wallsextending across said rectangular channel and being located closest saidopen end being a reflector, and a radiant energy heat source in saidheating zone located in spaced relationship to said reflector foremitting radiant energy against said reflector; a hood operativelyconnected by telescopic association to said unit and base housing forclosing said upper open end of said base housing; and a coolant fluidpump mounted on said hood for circulating coolant fluid along apaththrough said hood over a surface on the other side of the reflectorfrom said source for reducing the operating temperature of saidreflector. r

9. In a kiln, a base housing comprising four parallel corner memberseach L-shaped in section and located at respective corners of arectangle with adjacent flanges mutually coplanar to form a channelrectangular in cross section, four connecting members secured atopposite ends respectively to adjacent corner members and each beingL-shaped in section to form with one flange of each L-shape sides of therectangle and having the other respective flanges coplanar to form aborder closed bottom end of the rectangular channel with an open upperend, said corner members extending down beyond said plane to formsupporting legs for said kiln, said base housing having one side of therectangular channel forming the front side of the kiln with upper andlower U- shape channel members operatively connected at opposite ends tothe corner members forming the opposite edges of said front side, andtwo doors slidably connected in said U-shape channels between a kilnopen position in spaced apart relationship and a kiln closed positionwith said doors in abutting relationship; a unit having interconnectedbottom, opposite side, back, top and front walls forming an enclosedheating chamber with said ront wall including said doors, said unitadapted to be telescoped into said channel open end into assembledrelationship into said base housing with said bottom wall supported atthe bottom by said second recited flanges of said connecting members andsaid opposite side walls of said unit supported laterally by' saidcorner members and first recited flanges of said connecting members,said top wall extending across said rectangular channel and beinglocated closest said open end and being a metallic curved reflector withthe elements of the curve extending parallel to an axis, and a radiantenergy heat source being tubular in form with a longitudinal axis insaid heating chamber located in spaced relationship to said reflectorfor emitting radiant energy against said reflector, said opposite wallshaving through their inner faces coaxially aligned bores wherein saidtubular radiant energy heat source is mounted, said opposite side wallshaving in their inner surfaces thereof aligned grooves extending alongtheir elements parallel to the axis of said bores and curved in a planetransverse to the axis ,of said bores along the same curve as saidreflector, whereby said opposite side walls, reflector and radiantenergy heat source are assembled by approach movement of said side wallsalong said bore axis with the axes of said bores, source, and reflectorcurve oriented in the same direction and are disassembled by separationmovement of said side walls, said bottom and opposite side walls beingformed of fire brick; a hood operatively connected by telescopicassociation to said unit and base housing for closing said upper openend of said base housing; and a coolant fluid pump mounted on said hoodfor circulating coolant fluid along a path through said hood over asurface on the other side of the reflector from said source for reducingthe operating temperature of said reflector.

10. In a structure adapted to heat an object, a metallic reflectorincluding on the reflecting side thereof an aluminum base of highreflectivity with an oxide coating having a higher melting point thanthe aluminum base, a radiant energy heat source arranged in spacedrelationship to said reflector for emitting radiant energy against saidreflecting side, and a non-metallic reflector mounting element having ina surface thereof an arcuately shaped groove mounting said reflector outof contact with other metallic elements, said element being formed ofheat resistant ceramic material of low heat conductivity.

ii. In combination, a reflector, an electric radiant energy heat sourcelocated in spaced relationship to said reflector on one side of saidreflector for emitting radiant energy against said reflector to heatobjects to a temperature of at least 1000 C. in a heating zone, saidradiant energy heat source comprising a quartz envelope having oppositeends, having two electrically conductive terminals operatively securedto said opposite ends of said envelope, and having a tungsten filamentextending through said envelope and operatively connected to saidterminals and located in inert gas sealed in said envelope fortransforming electrical energy into radiant energy, leads from a commonelectrical source to each of said terminals, an electrical connectionbetween each lead and its associated terminal, said reflector beingsufliciently close to said source to be melted thereby if not cooled,said leads and terminals being sufficiently close to said source to havethe electrical circuit therethrough broken by heat if not cooled, meansfor forced circulating coolant fluid in thermal contact with saidreflector, at least a portion of said leads, said connections, and saidterminals for reducing their operating temperatures below either theirmelting points or the temperature breaking the electrical circuit, andmeans for preventing coolant fluid circulation through said heating zoneto reduce the temperature thereof.-

12. A structure, as set forth in claim 5, with a heating zone on-theinward side of said curved reflector, and means for forced circulatingcoolant fluid over the outward side of said curved reflector, saidreflector being telescoped into said grooves snugly enough to preventcooling of said heating zone by leakage therein of coolant fluid, saidside walls being of non-metallic material.

13; In combination, opposite walls forming a heating zone therebetweenfor temperatures of at least 1000 C.,

a reflector formed of heat conductive material, an electric radiantenergy heat source in said heating zone located in spaced relationshipto said reflector on one side of said reflector for emitting radiantenergy against a reflecting surface area on said one side, said electricradiant energy heat source comprising a quartz envelope having oppositeends, having two electrically conductive terminals operatively securedto said opposite ends of said envelope, and having a tungsten filamentextending through said envelope and operatively connected to saidterminals for transforming electrical energy into radiant energy andlocated in inert gas sealed in said envelope, leads from a commonelectrical source to each of said terminals, an electrical connectionbetween each lead and its associated terminal, means operativelyconnecting said source and said reflector to said walls so that saidwalls serve as a reflector shield to expose only said reflector surfacearea on said one side to said source, said opposite walls being formedof heat resistant ceramic material of low heat conductivity, said sourcebeing sufliciently high in temperature to melt said reflector and tobreak by the heat from this source the electrical circuit throughoutleads and connections and terminals if they are not cooled, means forcirculating coolant fluid along a path over and in thermal contact witha surface on the other side of the reflector from said sourceapproximately coextensive with and approximately aligned with saidsurface area, over at least a portion of said leads, over saidconnections, and over said terminals for reducing their operatingtemperatures below their melting point without cooling said envelope andheating zone, means for preventing circulation of said coolant fluid insaid heating zone, and means for preventing energizing said radiantenergy heat source without energizing said coolant fluid circulatingmeans.

14, In a kiln, a base housing comprising four parallel corner memberseach L-shaped in section and located at respective corners of arectangle with adjacent flanges mutually coplanar to form a channelrectangular in cross section, and four connecting portions secured toadjacent corner members and each being L-shaped in section to form withone flange of each L-shape sides of the rec-' tangle and with the otherrespective flanges coplanar to form a border closed bottom end of therectangular channel with an open upper end, said corner membersextending down beyond said plane to form supporting legs; and a unithaving interconnected walls forming at least a portion of a heating zonewith said unit adapted to be telescoped into said channel open end intoassembled relationship into said base housing and supported at thebottom by said second recited flanges of said connecting portions andlaterally by said corner members and first recited flanges of saidconnecting portions.

15. In a kiln, a base housing comprising four parallel corner memberseach L-shaped in section and located at respective corners of arectangle with adjacent flanges mutually coplanar to form a channelrectangular in cross section, and four connecting portions secured toadjacent corner members and each being L-shaped in section to form withone flange of each L-shape sides of the rectangle and having the otherrespective flanges coplanar to form a border closed bottom end of therectangular channel with an open upper end, said corner membersextending down beyond said plane to form supporting legs for said kiln;a unit having interconnected Walls forming at least a portion of aheating zone with said unit adapted to be telescoped into said channelopen end into assembled relationship into said base housing andsupported at the bottom by said second recited flanges of saidconnecting portions and laterally by said corner members and firstrecited flanges of said connecting portions, one of said walls extendingacross said rectangular channel and being located closest said open endbeing a reflector, and a radiant energy heat source in said heating zonelocated in spaced relationship to said reflector for emitting radiantenergy against said reflector; a hood operatively connected bytelescopic association to said unit and base housing for closing saidupper open end of said base housing; and a coolant fluid pump mounted onsaid hood for circulating coolant fluid along a path through said hoodover a surface on the other side of the reflector from said source forreducing the operating temperature of said reflector.

16. In combination, a reflector, a radiant energy heat source located inspaced relationship to said reflector on one side of said reflector foremitting radiant energy against said reflector, pump means for forcedcirculating coolant fluid in thermal contact with said reflector forreducing the operating temperature of said reflector, means forenergizing said heat source to a heat emitting relationship, means forenergizing said pump, and control means for preventing energizing saidradiant energy heat source by its energizing means without energizingsaid coolant fluid circulating pump means by its energizing means sothat said pump means must always be energized when said heat source isenergized so that the operating temperature will always be reduced, saidcontrol means including means for energizing said pump means by itsenergizing means without energizing said heat source means by itsenergizing means.

References Cited in the file of this patent UNITED STATES PATENTS714,373 Hewett Nov. 25, 1902 764,994 Dutertre July 12, 1904 1,231,196Rankin et al. June 26, 1917 1,802,001 Brooke Apr, 21, 1931 1,905,811Culver Apr. 25, 1933 2,131,484 Ringwald Sept. 27, 1938 2,358,718Kautfman et al. Sept. 19, 1944 2,400,056 Wheat May 7, 1946 2,439,005Jensen Apr. 6, 1948 2,497,676 Lashells Feb. 14, 1950 2,504,516 GoodellApr. 18, 1950 2,599,029 Turner et a1. June 3, 1952 2,627,014 Kolb Jan.27, 1953 2,707,745 Farr et al. May 3, 1955 2,764,664 Stewart Sept, 25,1956 2,822,458 Hatch Feb. 4, 1958 2,844,699 Miskella July 22, 1958FOREIGN PATENTS 338,816 Great Britain Nov. 27, 1930 484,199 GreatBritain Apr. 28, 1938 256,197 Switzerland Feb. 16, 1949 892,950 GermanyOct. 12, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2,981,819 April ac, lhl

' James Jo Gregory It is hereby certified that error appears in theabove numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 2, line 64, for "resing" read resting column 4, line 5, for "57"read 47 same line 5, for "relationsihp" read relationship line 7, Tor"tchis" read this line 55, for "Fahreinheit" read Fahrenheit line 57,for "'Fahrehiheit" read Fahrenheit column 6, line 54,

for "reactor" read reflector column 13, line 23, for

"throughout" read through the'--.

Signed and sealed this 17th day of October 1961.

(SEAL) Attest:

ERNEST SWIDER H DAVID L. LADD Commissioner of Patents Attesting OfficerUSCOM M- DC UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo, $981,819 April 25-, 15 61 James Jo Gregory It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below,

Column 2, line 64, for "resing" read resting -l; column 4, line 5, for"57" read 47 same line 5, for "relatiousihp" read relationship line 7,for "tthis" read this line 55, for "Fahreinheit". read Fahrenheit line57,

for "Fahrehiheit" read Fahrenheit column 6, line 54, for "reactor" readreflector r; column 13, line 23 for "throughout" read through the'-.

Signed and sealed lTth day of October 1961.,

(SEAL) Attest:

ERNEST W. SWIDER i -v DAVID L. LADD Attesting Officer Commissioner ofPatents USCOMM-DC

